U.S. patent application number 11/350601 was filed with the patent office on 2007-08-09 for dome-loaded pressure regulators.
Invention is credited to Todd William Larsen.
Application Number | 20070181198 11/350601 |
Document ID | / |
Family ID | 38267504 |
Filed Date | 2007-08-09 |
United States Patent
Application |
20070181198 |
Kind Code |
A1 |
Larsen; Todd William |
August 9, 2007 |
Dome-loaded pressure regulators
Abstract
Dome-loaded pressure regulators are disclosed. An example
pressure regulator includes body having a pressure inlet and a
pressure outlet. A piston is disposed in the body and fluidly
coupled to the pressure inlet, the pressure outlet, and the
pressure control inlet. The piston is configured to contact a valve
seat and to control the flow of fluid from the pressure inlet to
the pressure outlet in response to a pressure applied to a surface
of the piston via the pressure control inlet.
Inventors: |
Larsen; Todd William;
(Milaca, MN) |
Correspondence
Address: |
HANLEY, FLIGHT & ZIMMERMAN, LLC
150 S. WACKER DRIVE
SUITE 2100
CHICAGO
IL
60606
US
|
Family ID: |
38267504 |
Appl. No.: |
11/350601 |
Filed: |
February 9, 2006 |
Current U.S.
Class: |
137/883 |
Current CPC
Class: |
G05D 16/0404 20190101;
Y10T 137/7834 20150401; Y10T 137/7762 20150401; G05D 16/106
20130101; G05D 16/187 20190101; Y10T 137/7835 20150401; Y10T
137/87877 20150401 |
Class at
Publication: |
137/883 |
International
Class: |
F16K 11/22 20060101
F16K011/22 |
Claims
1. A pressure regulator, comprising: a body having a pressure inlet
and a pressure outlet; and a piston disposed in the body and
fluidly coupled to the pressure inlet, the pressure outlet, and the
pressure control inlet, wherein the piston is configured to contact
a valve seat and to control the flow of fluid from the pressure
inlet to the pressure outlet in response to a pressure applied to a
surface of the piston via the pressure control inlet.
2. A pressure regulator as defined in claim 1 further comprising a
fluid restrictor serially interposed in a fluid path fluidly
coupling the pressure control inlet to a chamber associated with
the surface of the piston.
3. A pressure regulator as defined in claim 1, wherein the piston
comprises a central bore having an annular surface configured to
sealingly engage the valve seat.
4. A pressure regulator as defined in claim 1 further comprising a
spring to bias the piston into contact with the valve seat.
5. A pressure regulator as defined in claim 1 further comprising a
plurality of sealing rings engaged with the piston.
6. A pressure regulator as defined in claim 5, wherein at least one
of the sealing rings is an o-ring.
7. A pressure regulator as defined in claim 1, wherein the valve
seat is a plug-shaped member.
8. A pressure regulator as defined in claim 1, wherein the valve
seat is made substantially of a plastic material.
9. A pressure regulator as defined in claim 1 further comprising a
second pressure regulator disposed in the body and coupled to the
fluid inlet, wherein the second pressure regulator comprises a
second piston disposed in the body and fluidly coupled to the
pressure inlet, a second pressure outlet, and a second pressure
control inlet, wherein the second piston is configured to contact a
second valve seat and to control the flow of fluid from the
pressure inlet to the second pressure outlet in response to a
second pressure applied to a surface of the second piston via the
second pressure control inlet.
10. A pressure regulator, comprising: a dome-loaded pressure
regulating valve fluidly coupled to a pressure inlet, a pressure
outlet, and a control pressure, wherein the pressure regulating
valve comprises a piston configured to engage a valve seat and to
respond to the control pressure to control the flow of fluid
between the pressure inlet and the pressure outlet via the valve
seat.
11. A pressure regulator as defined in claim 10, wherein the piston
is springably biased toward engagement with the valve seat.
12. A pressure regulator as defined in claim 10, wherein the piston
is a substantially unitary member.
13. A pressure regulator as defined in claim 10, wherein the piston
comprises a passage having an annular surface to engage the valve
seat.
14. A pressure regulator as defined in claim 10, wherein the piston
has a surface to receive the control pressure.
15. A pressure regulator as defined in claim 14, wherein the
surface of the piston is fluidly coupled to the control pressure
via a fluid restrictor.
16. A pressure regulator, comprising: a body having a pressure
inlet and first and second pressure outlets; and first and second
pressure regulating valves disposed in the body and fluidly coupled
to the pressure inlet and the respective first and second pressure
outlets, wherein each of the first and second pressure regulating
valves includes a piston having a first portion to receive a
control pressure and a second portion fixed to the first portion
and configured to sealingly engage a valve seat.
17. A pressure regulator as defined in claim 16, wherein each of
the pistons includes a plurality of sealing rings configured to
frictionally engage the body.
18. A pressure regulator as defined in claim 16, wherein the first
portion of each of the pistons is fluidly coupled to its respective
control pressure via a respective fluid restrictor.
19. A pressure regulator as defined in claim 16, wherein each of
the pistons is springably biased toward engagement with its
respective valve seat.
20. A pressure regulator as defined in claim 16, wherein each of
the first and second pistons is made of substantially one-piece of
material.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclose relates generally to pressure
regulators and, more particularly, to dome-loaded pressure
regulators.
BACKGROUND
[0002] Many process control systems use pressure regulators to
control the pressure of a process fluid, to control a pressure
applied to a process control device (e.g., an actuator), etc.
Pressure reducing regulators are commonly used to receive a
relatively high pressure fluid source and output a relatively lower
regulated output fluid pressure. In this manner, despite the
pressure drop across the regulator, a pressure reducing regulator
can provide a relatively constant output fluid pressure for a wide
range of output loads (i.e., flow requirements, capacity,
etc.).
[0003] Some pressure reducing regulators commonly referred to as
dome-loaded pressure reducing regulators utilize a dome or pilot
stage that receives a control pressure (e.g., a setpoint pressure
or desired output pressure). The control pressure in the dome or
pilot stage typically drives a sensor (e.g., a piston) which, in
turn, drives a valve stem and its plug against a bias spring toward
or away from a valve seat so that the output pressure of the
regulator substantially equals the control pressure.
[0004] However, such dome-loaded regulator designs typically use a
separate piston or sensor and valve plug/stem assembly. Due to the
separate piston and valve plug/stem assemblies, these types of
regulators are prone to overshooting/undershooting a target output
pressure and/or may produce an oscillating output pressure. In
particular, because the piston is not mechanically joined to the
valve stem, the piston can separate from the valve stem/plug
assembly resulting in a transitory or momentary loss of control
over the position of the plug relative to the seat. As a result,
these types of pressure reducing regulator designs may produce
unstable (overshooting, undershooting, oscillating, etc.) output
pressures in response to rapid changes in the dome pressure (i.e.,
the control pressure). For example, in some known applications,
control pressure or dome pressure is supplied or controlled via
fast acting solenoid valves, which produce rapid pressure changes
in the dome and, thus, aggravate the above-described stability
problem associated with these known dome-loaded regulators. In
addition to the stability issues associated with known dome-loaded
pressure reducing regulator designs, the above-described
dome-loaded pressure reducing regulators utilize a relatively large
number of parts, which tends to increase the material and
maintenance cost of the regulators as well as the likelihood of
regulator failure.
[0005] A pressure reducing regulator having relatively few moving
parts and a substantially unitary piston or sensor and valve plug
assembly is described in U.S. Patent Publication No. 2004/0007269,
the entire disclosure of which is incorporated herein by reference.
The pressure reducing regulator described in this patent
application publication is an in-line pressure reducing regulator
that does not utilize a pilot stage or dome to control output
pressure and, instead, uses springs to establish a predetermined
output pressure. In addition to reducing the number of moving
parts, the substantially unitary piston or sensor and valve plug
assembly also eliminates the possibility of the valve plug from
separating from the piston/sensor, as can occur with the
dome-loaded regulator designs noted above.
[0006] Still further, in some applications it is desirable to
provide multiple pressure outputs (which may be different pressure
values) derived from a single source pressure. Commonly, such
multiple output pressure applications are implemented by fluidly
coupling two or more pressure reducing regulator assemblies, such
as the dome-loaded regulators described above, via a manifold
and/or tubing. However, such multiple output regulator assemblies
are typically expensive to assemble, bulky, heavy, difficult to
maintain, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is cross-sectional view of a known dome-loaded
pressure reducing regulator.
[0008] FIG. 2 is a cross-sectional view of an example dual output
dome-loaded pressure reducing regulator.
SUMMARY
[0009] In one disclosed example, a pressure regulator includes a
body having a pressure inlet and a pressure outlet. A piston is
disposed in the body and fluidly coupled to the pressure inlet, the
pressure outlet, and the pressure control inlet. The piston is
configured to contact a valve seat and to control the flow of fluid
from the pressure inlet to the pressure outlet in response to a
pressure applied to a surface of the piston via the pressure
control inlet.
[0010] In another disclosed example, a pressure regulator includes
a dome-loaded pressure regulating valve fluidly coupled to a
pressure inlet, a pressure outlet, and a control pressure. The
pressure regulating valve includes a piston configured to engage a
valve seat and to respond to the control pressure to control the
flow of fluid between the pressure inlet and the pressure outlet
via the valve seat.
[0011] In still another disclosed example, a pressure regulator
includes a body having a pressure inlet and first and second
pressure outlets. The example regulator also includes first and
second pressure regulating valves disposed in the body and fluidly
coupled to the pressure inlet and the respective first and second
pressure outlets. Each of the first and second pressure regulating
valves includes a piston having a first portion to receive a
control pressure and a second portion fixed to the first portion
and configured to sealingly engage a valve seat.
DETAILED DESCRIPTION
[0012] In general, the example multiple output dome-loaded pressure
reducing regulator described herein provides one regulator body
that holds multiple pressure regulating valves. Each of the
pressure regulating valves provides an independent pressure output
or outlet and the independent pressure outputs are derived from a
single pressure source inlet of the regulator body.
[0013] Additionally, in contrast to some known dome-loaded the
pressure regulating valves, the example multiple output pressure
reducing regulator described herein utilize pressure regulating
valves having a substantially unitary or integrated piston or
sensor and valve assembly that substantially reduces or eliminates
output pressure instabilities (e.g., overshooting, undershooting,
oscillation, etc.) such as those that may result from rapid changes
in dome or control pressure. The integrated piston or sensor and
valve assembly also serves to reduce the number of parts needed to
implement the pressure regulating valves in comparison to some
known pressure regulating valves, thereby enabling a more compact
design, improved reliability, and lower costs.
[0014] Thus, the example integrated multiple output regulator
configuration described herein provides a multiple output regulator
assembly having a single regulator body that eliminates the need
for numerous fittings, tubing, bulky and expensive manifolds, etc.,
as was required for some known multiple output regulator designs.
Further, the pressure regulating valves used to implement the
example multiple output regulator have fewer internal components.
As a result, the example multiple output regulator assembly
described herein may provide lower manufacturing/fabrication costs
in addition to lower maintenance costs due to the improved
reliability that results from having fewer overall components.
[0015] Before discussing the example multiple output pressure
reducing regulator of FIG. 2, a known dome-loaded pressure reducing
regulator 100 is first described in connection with FIG. 1. The
known pressure reducing regulator 100 of FIG. 1 includes a body 102
having an inlet 104, an outlet 106, and a pilot or control pressure
input 108. A plug or bonnet 110 is threaded into the body 102 to
form a chamber or dome space 112. An o-ring 114 forming a seal
against an inner passage 116 of the body 102 is backed by a ring
118 to prevent extrusion of the o-ring 114 between the bonnet 110
and the body 102. A piston or sensor 120 is slidably engaged with
the passage 116 and includes an o-ring 122 and backing rings 124
and 126 to form a seal against the passage 116. The piston 120
contacts a valve assembly 128 via a shaft 130 of a plug 132. The
plug 132 is urged or biased toward or against a seat 134 via a
spring 135.
[0016] In operation, a desired control pressure is applied to the
pilot input 108 and, thus, to the piston 120. If the pressure at
the outlet 106 is less than the control pressure, the piston 120 is
displaced toward the valve seat 134 to drive the plug 132 away from
the seat 134. As a result, the restriction between the inlet 104
and the outlet 106 decreases to enable the pressure at the outlet
106 to increase. As the pressure at the outlet 106 increases, the
amount of pressure urging the piston 120 away from the valve seat
134 increases. When the pressure applied to a first face 136 of the
piston 120 (i.e., the pressure at the pilot inlet 108) is
substantially equal to the pressure applied to a second face 138 of
the piston 120 (i.e., the pressure at the outlet 106), the piston
120 will remain relatively stationary within the passage 116 and
the pressure at the outlet 106 will remain substantially constant
and equal to the pressure at the pilot input 108.
[0017] However, the known dome-loaded pressure reducing regulator
100 of FIG. 1 is susceptible to output pressure instability. For
example, in some applications, the dome pressure supply (i.e., the
pressure applied at the pilot input 108) to the regulator 100 is
controlled using two solenoid valves (neither of which are shown).
One solenoid valve opens to introduce air pressure into the dome
space 112 via the pilot input 108 and the other solenoid valve
bleeds pressure out of the dome space 112 via the pilot input 108.
While such a solenoid configuration provides a fast acting method
of introducing high-pressure air into the regulator dome space 112,
the configuration is relatively susceptible to instability (e.g.,
overshooting, undershooting, oscillations, etc.). More
specifically, the rapid introduction of air (e.g., the introduction
of a quick burst of air) into the dome space 112 may cause the
regulator 100 to open quickly to a maximum flow condition, which
then causes the output pressure of the regulator 100 to overshoot.
In response to the output pressure overshoot, the valve 128 in the
regulator 100 closes rapidly, which causes the regulator output
pressure to undershoot the desired control pressure. Thus, this
instability can result in a succession of pressure overshoots and
undershoots or continuous oscillation of the regulator output
pressure.
[0018] FIG. 2 is a cross-sectional view of an example dual output
dome-loaded pressure reducing regulator 200. The example dual
output dome-loaded pressure reducing regulator 200 includes first
and second pressure reducing regulators 202 and 204 having
respective pressure reducing valve assemblies 206 and 208. As shown
in FIG. 2, the regulators 202 and 204 are disposed within a single
substantially unitary body 210, which may be made of metal such as,
for example, brass, stainless steel, or any other metal or material
suitable for the intended application of the pressure reducing
regulator 200. The body 210 includes a single pressure inlet 212,
which provides a pressure source to the regulators 202 and 204 and
independent multiple or dual pressure outlets or outputs 214 and
216, corresponding to the respective first and second regulators
202 and 204.
[0019] Turning in detail to the first regulator 202, a bonnet or
cap 218 is threadingly and sealingly engaged with the body 210. The
bonnet 218 provides a pilot or pressure control inlet or input 220,
which forms a fluid passage 222 to a chamber or dome space 224. As
depicted in the example of FIG. 2, a fluid restrictor 226 may be
interposed in the fluid path between the pressure control inlet 220
and the chamber 224.
[0020] A sensor or piston 228 slidably engaged with the body 210 is
fluidly coupled to the pressure inlet 212, the pressure outlet 214
and the pressure control input 220 via the chamber 224 and the
passage 222. The piston 228 has a first portion 230 having a
surface 232 that receives a pressure (i.e., the pressure in the
chamber or dome space 224) via the pressure control input 220.
Additionally, the piston 228 has a second portion 234 configured to
contact a valve seat 236 and to control the flow of fluid from the
pressure inlet 212 to the pressure outlet 214 in response to the
pressure applied to the surface 232 of the piston 228 via the
pressure control input 220. In contrast to some known dome-loaded
pressure reducing regulators and regulating valves, the first and
second portions 230 and 234 of the piston or sensor 228 are fixed
together (i.e., cannot separate during operation of the valve 206)
and, thus, form a substantially one-piece or unitary member.
[0021] The valve seat 236 may be a plug-shaped member made
substantially of a plastic material, or any other material that is
relatively softer than the material composing the piston 228. A
spring 238 disposed between a seat portion 240 of the body 210 and
a shoulder 242 of the piston 228 biases an annular surface 244 of a
central bore 245 of the piston 228 toward or into sealing
engagement or contact with the valve seat 236. A plurality of
circumferential seals (e.g., o-rings) 246, 248, and 250 disposed in
respective annular channels or grooves 252, 254, and 256 sealingly
engage the body 210 and the bonnet 218. The seal 250 further
includes a backing ring 258 to inhibit or prevent extrusion of the
seal 250 from its groove 256.
[0022] In operation, a control pressure (e.g., a desired output
pressure) is applied to the pilot or pressure control input 220.
The control pressure then pressurizes the dome space or chamber 224
via the fluid restrictor 226. In this manner, the fluid restrictor
226 prevents an overly rapid increase (or decrease) of the pressure
applied to the surface 232 of the piston 228 and, thus, tends to
substantially reduce or eliminate pressure instabilities (e.g.,
overshooting, undershooting, oscillation, etc.) at the outlet 214.
For example, when solenoid valves (not shown) are used to increase
(i.e., load) or decrease the pressure in the dome space 224, the
fluid restrictor 226 slows the flow of air to/from the dome space
224 to the solenoid valves, which slows the movement of the piston
228 to prevent the piston 228 and, thus, the pressure at the outlet
214 from oscillating or cycling about a desired output
pressure.
[0023] During operation, the control pressure applied to the piston
surface 232 via the inlet 220 urges the piston 228 against the
force of the spring 238 to move the annular surface 244 away from
the seat 236, which decreases the restriction between the inlet 212
and the outlet 214 to enable the pressure at the outlet 214 to
increase. As the pressure at the outlet 214 increases, the pressure
against the shoulder 242 and surface 260 of the piston urges the
piston 228 against the pressure in the dome or chamber 224 to move
the annular surface 244 toward the seat 236, which increases the
restriction between the inlet 212 and the outlet 214 to enable the
pressure at the outlet 214 to decrease (or to stop increasing).
When the pressures urging the annular surface 244 away from the
seat 236 and toward the seat 236 are in balance, the pressure at
the outlet 214 is substantially equal to the pressure provided via
the pressure control inlet 220 to the dome or chamber 224.
[0024] In addition to sealing the piston 228 to the body 210, the
seals 246, 248, and 250 also serve to increase the output stability
of the regulator 202. More specifically, the seals 246, 248, and
250 provide a frictional engagement with the body 210 that dampens
the movements of the piston 228 in response to relatively rapid
pressure changes or perturbations at the inlet 212, the pressure
control input 220, and/or the outlet 214.
[0025] The substantially one-piece or unitary piston 228 further
enhances stable operation of the regulator 202. In particular,
unlike some known dome-loaded pressure regulators, the plug or
sealing surface (e.g., the sealing surface 244) is integral with
the piston or sensor 228, thereby eliminating any possibility of
separation between the mechanism controlling the flow of fluid past
the seat 236 and the mechanism that senses or which is exposed to
and which is responsive to the pressure in the dome space 224.
[0026] The bias provided by the spring 238 causes the sealing
surface 244 to sealingly contact or engage the seat 236 in the
absence of a control pressure in the dome space 224 (e.g., zero
pounds per square inch gauge). In this manner the regulator valve
206 is configured as a normally-closed device. Additionally, the
regulator valve 206 provides a positive (e.g., self-healing) seal
design. For example, if the seat 236 develops a leak from debris or
any imperfection associated with the sealing surface 244 and/or the
seat 236, the pressure at outlet 214 will increase and apply a
greater force on the shoulder 242 and the surface 260 of the piston
228 to drive the sealing surface 244 against the seat 236. In the
case where the seat 236 is made of a relatively softer material
(i.e., softer than the surface 244 of the piston 228) such as, for
example, plastic, the seat is deformed and/or conforms to
accommodate the imperfection, debris, etc. to seal against the
surface 244. Once deformed or conformed to the surface 244, the
leakage past the seat 236 is substantially reduced or
eliminated.
[0027] The second pressure reducing regulator 204 and valve 208 is
formed using the same components as those used for the first
regulator 202 and, thus, the second regulator 204 and its valve 208
are not described in greater detail herein. Additionally, although
not shown, safety or relief valves may be added to the outlets 214
and 216 of the regulators 202 and 204, and an inlet filter may be
placed in the inlet 212 to prevent debris from reaching the valves
206 and 208 and, in particular, the valve seats (e.g., the seat
236). It should be noted that the pressures in the dome spaces
(e.g., 224) of the regulators 202 and 204 do not have to be equal
(i.e., the regulators may receive different pilot or control
pressures and, thus, different output pressures). Likewise, the
fluid restrictors (e.g., 226) may be sized or configured similarly
or differently to achieve desirable fill and/or bleed rates.
[0028] Further, it should be understood that while the example
pressure reducing regulator 200 of FIG. 2 includes two pressure
reducing regulators, alternative designs may include only one such
regulator or more than two regulators to suit a particular
application. In one alternative example, an additional regulator
may be bolted or otherwise fixed to the regulator 200. In that
case, an additional inlet port connects to the inlet of the added
(e.g., third) regulator and the outlet of the additional (e.g.,
third) regulator feeds pressure to the domes (e.g., the dome space
224) of the regulators 202 and 204. Alternatively, the outlet of
the added regulator may feed solenoids, which would serve to
control the pressure in the domes (e.g., the dome space 224).
[0029] In addition to providing a highly stable output pressure,
the configuration of the example regulator 200 eliminates the need
for several fittings such as, for example, elbows, tees, etc. in
comparison to known multiple outlet pressure reducing regulators.
In addition, the example regulator 200 has a relatively smaller
overall size and is lighter weight in comparison to known multiple
output regulators. Still further, the example regulator 200 has
relatively few internal parts and, thus, the cost of the example
regulator 200 may be lower and the reliability may be higher than
known multiple output regulators.
[0030] Although certain apparatus, methods, and articles of
manufacture have been described herein, the scope of coverage of
this patent is not limited thereto. To the contrary, this patent
covers all embodiments fairly falling within the scope of the
appended claims either literally or under the doctrine of
equivalents.
* * * * *